#include <stdio.h>
#include <stdlib.h>

#define CNTL_Z '\032'  //DOS文本文件中的文件结尾标记
#define SLEN 81

int main(void) {
    char file[SLEN];
    char ch;
    FILE *fp;
    long count, last;

    puts("Enter the name of the file to be processed:");
    scanf("%80s", file);
    if ((fp = fopen(file, "rb")) == NULL) {
        //只读模式
        printf("reverse can't open %s\n", file);
        exit(EXIT_FAILURE);
    }

    fseek(fp, 0L, SEEK_END);
    last = ftell(fp);
    for (count = 1L; count <= last; count++) {
        fseek(fp, -count, SEEK_END);   //回退
        ch = getc(fp);
        if(ch != CNTL_Z && ch != '\r') //MS-DOS文件
            putchar(ch);
    }
    putchar('\n');
    fclose(fp);

    return 0;
}
